One of the difficult constraints associated with an imaging array is to provide a reasonable nozzle density while minimizing the print head in the drum motion direction, called waterfront. The reason for this constraint is that the curvature of the drum on which the drops are printed creates different flight distances and arrival times for the drops from different nozzle arrays in a four color print head. Unless the nozzle arrays are close together, the resulting image will have defects. Exacerbating this issue is the fact that most printing arrays composed of subunits choose to stagger the subunits to avoid the difficult issues entailed in tightly butting the subunits. While the staggered architecture avoids the butting issues, it exacerbates the issue of waterfront, since the depth of the imaging array must now be at least twice the depth of a single die.
FIG. 1 shows a conventional, single color staggered imaging array 100. In particular, a conventional staggered imaging array 100 relying on micro electromechanical system (MEMS) technology includes staggered MEMS dies 110a-110d and associated driver dies 120a-d. 
Driver die 120a provides driver functionality for MEMS die 110a. Driver die 120b provides driver functionality for MEMS die 110b. Driver die 120c provides driver functionality for MEMS die 110c. Driver die 120d provides driver functionality for MEMS die 110d. 
MEMS dies 110a and 110b are slightly staggered with respect to one another to double the resolution as compared to use of an individual MEMS die 110b. For example, if the nozzle resolution of die 110a is 150 nozzles per inch, the resolution of the slightly staggered pair 110a and 110b is 300 nozzles per inch. MEMS dies 110c and 110d are slightly staggered with respect to one another to double the resolution as compared to use of an individual MEMS die 110c. MEMS die 110a and 110b can easily be combined into a single die with a fill slot in between the two arrays; likewise for die 110c and 110d. In any case, it is desirable for die 110a and 110b to be staggered relative to die 110c and 110d to avoid the difficult butting issues of trying to precisely and tightly butt die 110a and 110b with die 110c and 110d. 
It would be desirable that the waterfront of the conventional staggered imaging array 100 is minimized, ideally no greater than the depth of the MEMS die 110a+110b+110c+110d=10 mm in this example. However, because the driver dies 120a and 120d must be arranged next to their respective MEMS dies 110a and 110d the resultant full depth of the conventional staggered imaging array from top to bottom is approximately 15 mm because it must include the added depth of the two driver die. In this example, the depth of the staggered imaging array is 15 mm, even though the depth of the MEMS die is only 10 mm. With space constraints (waterfront) inside of a printer device utilizing an imaging array 100 becoming increasingly more limited, a 15 mm depth for each conventional imaging array 100 can become a relevant design constraint.
Accordingly, the present teachings solve these and other problems of the prior art's depth of an imaging array.